About Alanine Transaminase (ALT)
Alanine Transaminase (ALT) is an enzyme primarily found in the liver. It plays a vital role in amino acid metabolism and is used as a marker for liver health. Elevated ALT levels typically indicate liver inflammation or damage, as ALT is released into the bloodstream when liver cells are compromised.
Reference Values
Optimal Range
7.0 - 35.0 U/L
Women's Optimal Range
7.0 - 30.0 U/L
Elite Value
Not specified
Health Implications
High
Elevated levels may indicate liver damage or inflammation, often due to conditions like hepatitis or excessive alcohol use. Persistently high ALT could also hint at heart or kidney disease.
Low
Low levels may be associated with general good liver health, but in rare cases, could hint at surface factors such as malnutrition or a vitamin B6 deficiency.
Symptoms
High
May include fatigue, abdominal pain, dark urine, jaundice, and unexplained weight loss.
Low
Can include decreased muscle coordination, dizziness, and persistent feeling of fatigue.
Lifestyle Factors
Specimen Type
Testing Methods
Also Known As
Scientific Sources
- Kim, W. R., Flamm, S. L., Di Bisceglie, A. M., & Bodenheimer, H. C. (2008). Serum activity of alanine aminotransferase (ALT) as an indicator of health and disease. Hepatology, 47(4), 1363-1370.
- Prati, D., Taioli, E., Zanella, A., Della Torre, E., Butelli, S., Del Vecchio, E., ... & Colombo, M. (2002). Updated definitions of healthy ranges for serum alanine aminotransferase levels. Annals of Internal Medicine, 137(1), 1-10.
- American College of Gastroenterology. (2017). ACG clinical guideline: evaluation of abnormal liver chemistries. The American Journal of Gastroenterology, 112(1), 18-35.
- European Association for the Study of the Liver. (2019). EASL clinical practice guidelines: management of patients with decompensated cirrhosis. Journal of Hepatology, 69(2), 406-460.
- American Association for the Study of Liver Diseases. (2018). AASLD guidelines for the treatment of chronic hepatitis B. Hepatology, 67(4), 1560-1599.